Saturday, September 10, 2005

Rumen Power

I've posted a number of items in recent months on microbial fuel cell developments, and now National GeographicNewspoints out yet another variation on this theme:

Researchers found they could generate electricity using the bacteria that occur naturally inside a cow's rumen—the first of four stomachs that breaks down grass and other fodder into a digestible mush.

The bovine stomach bacteria add to a growing list of cheap, plentiful, and non-polluting substances that run devices known as microbial fuel cells (MFCs)....

Researchers at Ohio State University found that a pint (half a litre) of a cow's bacteria-infested rumen juice produced about 600 millivolts of electricity. The output is about half the voltage of a rechargeable AA-size battery.

Ann D. Christy, professor of food, agricultural, and biological engineering, said the team tapped into the electron transport system of rumen bacteria.

"The normal metabolism of electro-chemically active micro-organisms allows them to generate a small electrical current when placed in contact with the anode [negative electrode] of the microbial fuel cell," she said.

The cathode, the positive electrode of the experimental battery, was filled with a chemical oxidizing (electron-removing) agent to round out the electrical circuit.

So does this mean that slaughterhouses could also become energy production facilities? This article points to several other developments, including other research at Ohio State on microbial processes with cow dung, and a British experiment with robots that run on flies... really.